Per Page CSS Selection

This might come close to what you want.

Add the below code inside your theme functions.php. Then create a new css file, the filename is base on your user “login” name (i.e, login-name.css, jake.css, admin.css) then upload it within your template root directory (same location with the functions.php).

/**
 * Auto include author stylesheet on WP single and custom page view.
 * @author Avice D (ChaosKaizer)
 * @see WP_Styles
 */
function wp_auto_include_author_css()
{ global $wp_query;

	$css_path = TEMPLATEPATH.DIRECTORY_SEPARATOR;
	$css_url = get_bloginfo('template_url').'/';

	if ($wp_query->is_single || $wp_qeury->is_page){
		$po = $wp_query->get_queried_object();

		$author_name = sanitize_title_with_dashes(strtolower(get_author_name($po->post_author)));

		unset($po);		

		$filename = $author_name.'.css';
		$handle = $author_name.'-stylesheet';

		if (file_exists($css_path.$filename)){

			wp_register_style($handle, $css_url.$filename);
			wp_enqueue_style($handle);
			wp_print_styles();
		}
	}
}

add_action('wp_head','wp_auto_include_author_css');

If your log-in name is “John Doe” it will look for john-doe.css. Space is replace with dash and all characters is in lowercase.

true, my mistake ;(

find

if ($wp_query->is_single || $wp_qeury->is_page){

replace with

if ($wp_query->is_single || $wp_query->is_page){

..

/**
 * Auto include author stylesheet on WP single and custom page view.
 * @author Avice D (ChaosKaizer)
 * @see WP_Styles
 */
function wp_auto_include_author_css()
{ global $wp_query;

	$css_path = TEMPLATEPATH.DIRECTORY_SEPARATOR;
	$css_url = trailingslashit(get_bloginfo('template_url'));

	if ($wp_query->is_single || $wp_query->is_page){
		$po = $wp_query->get_queried_object();

		$author_name = sanitize_title_with_dashes(strtolower(get_author_name($po->post_author)));

		unset($po);		

		$filename = $author_name.'.css';
		$handle = $author_name.'-stylesheet';

		if (file_exists($css_path.$filename)){

			wp_register_style($handle, $css_url.$filename);
			wp_enqueue_style($handle);
			wp_print_styles();
		}
	}
}

add_action('wp_head','wp_auto_include_author_css');